My questing army was moving through Rolling plains when I received a message that I was under attack. It was my first PvP field battle. It did not go well, I lost my entire army. I was a little dissapointed because these were my initial units that I had been nursing from the beginning. Some of the higher units had reached level 8.

Heading back to my city I started to rebuild my army with my 1 Barracks, 1 Stable, 1 Archery Range. All were at level 1. It was taking forever and I was not looking forward to leveling my army back up.

While waiting for my army to rebuild, I decided to change the way I produced my army, There may be a better way, but here is how am doing it:

I have built multiple troop producing buildings and leveled them all to level 5. (This makes the units they produce start at level 5)

It takes the following amount of gold to level a unit from level 5 to level 10 in a training ground:

Barracks:
Swordsman 2889
Maceman 1734
Halberdier 2310

Stables:
Ft.Knight 4620
Mtd Knight 5773
Cavalier 4620

Archery Range:
Archer 2772
Crossbow 3465

So I build an Army at level 5, run them over to the Capitol and train them to level 10.

I really do recommend you leveling your unit producing buildings to level 5, here's why:
It takes a total of 2500 Food, 5000 Wood, 1125 Stone, and 8 Wealth to level a Stables to level 5 (for my race/region selection)

To level a unit of Knights from 1 to 10 is 5940 Gold

Leveling the same unit produced in a level 5 Stable from level 5 to 10 is 4620 Gold. A difference of 1320 Gold

As you can see, it would not take very many units to pay for the difference in costs.